The U.S. Department of Energy has estimated that residential electricity usage in the U.S. amounts to approximately 33% for cooling (air conditioners, refrigerators, and freezers), 25% for heating (space heaters, water heaters, and clothes dryers), 9% for lighting, and 33% for other appliances. This usage distribution is most likely not optimal and one of the significant challenges to an electric utility is planning, evaluating, and offering various energy efficiency and demand response programs to optimize the situation. For example, if most swimming-pool pumps in the utility's service territory run completely or partially during peak electricity usage hours during the day in the summer then a pool pump demand response program is extremely desirable.